Hi KDettman

I think only way this to be done is by following the article below:
https://help.k2.com/onlinehelp/k2smartforms/devref/4.7/default.htm#Creating_a_Custom_Theme.html

Should you find the information from the article useful or leading you to the answer please mark as "Solution and/or Kudo", as it will assist other k2 developers with relevant information in the near future.

Best Regards

Elvis

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Good day KDettman

The theme property being disabled by default when using the set form properies is as per design however and nice workaround would be to call your form with the desired theme via the URL, for example: Lets say you have form1 which consists of URL https://server.com/Runtime/Runtime/Form/Form1/  you can simply call this form using a navigate to URL rule and modify the URL by adding the below into the URL which would change your URL to look like this:  https://server.com/Runtime/Runtime/Form/Form1/?_theme=Platinum

?_theme=Platinum

*Note: You would need to replace the red section with the correcly spelled theme name, and the theme must be part or the system. This also works with custom build themes that are visibile in K2 designer. https://help.k2.com/onlinehelp/k2smartforms/devref/4.7/default.htm#Creating_a_Custom_Theme.html

Please keep in mind that this will only work with forms and will not work with views.

Kind Regards

Raymond